Making sodium formate formic acid compounds



Patented Nov. 29, 1927.

UNITED STATES PATENT OFFICE.

Econ anon, on xanLsnunE, GERMANY, assrenon To mm m nunonrn noun a 00., or OESTRIGH-ON-THE-BHINE, ennum.

MAKING sonnm roman ronmc ACID comrounns.

' Ne Drawing. Application filed September 24, '1923, Serial no. 664,573, and m- Austria September 5, 1922.

According to the present invention the production of a sodium formate-formic-acid compound of different percentages of acid is obtained in a surprisingly simple manner by the treatment of sodium formate with aqueous formic acid.

The process of the invention may be carried out by adding commercial sodium formate to aqueous formic acid of which the acid content exceeds'20%, the treatment be-' ving at elevated temperatures.

Onqcgoling the mixture to normal temperatures', "a sodium formate-formic acid compound-separates in the-form of well defined crystals which may be separated from the mother liquor by submitting the mixture to centrifugal force.

If an aqueous formic acid having an acid content of less than 50% is employed, a com-- pound of three molecules of sodium formate with one of formic acid is obtained, that is, HCOOH.3HCOONa; While if the acid content exceeds 50%, either sodium biformate or a mixture of the two sodium-formateformic acid compounds is obtained. The

compound of three molecules of sodium formate with one of formic acid may be converted into sodium biformate in the simplest manner, for instance, by simply agitating 3 it with an aqueous.formic acid of suitable concentration, for instance, 60%.-

The trisodiumhydroformate (ncoonancooua is always formed on the addition of sodium formate to aqueous formic acid of 20 to 50% acid content. In the use of formic acid of more than 50% there is produced, according to the working conditions, either biformat'e I 40 ,or a mixture of biformate and triformate,

or only triformate, according to. the mass,

relations in which the acid and formate are? used. If a definite amount of formic acid of more than 50% is added to sodium formate, there separates out first-biformate, with a binding of the formic acid, which has as a result a decrease of the acid content. If now sodium formate is further added until the acid content comes backto 50%, the formation of trlsodmmhydroformate will begin at the cost of the b1for-. mate and there will be obtained a mixture of biand tri-formates, while the acid concentration remains constant at 50%. Upon .From then on" only .the trisodiumhydroformate is formed, while the acid concentration gradually comes back to 20%.

Eaamplea.

(l) 100 kilograms of aqueous formic acid of 50% acid content is brought in contact with 100 kilograms of'commercial sodium formate. After cooling the mixture resultmg from the reaction to-normal temperature, 160 kilograms of. trisodiumhydroformate (HCOOH.3HCOONa) can be obtamed from the mother liquor. The mother liquor, which is about 30% formic acid sat urated with sodium formate, can be used subsequentl for any desired purpose, for instance, a er addition of a stronger acid, for the preparation of a new mixture.

(2) 110 kilograms of sodium formate are m xed with 100 kilograms of 80% formic acid. After the cooling of the mixture 114 kllograms of sodium biformate can be obtamed at normal temperature upon precipitatlon. The mother liquor consists of about 60% formic acid saturated with sodium formate and it can be used for the direct production of trisodiumhydroformate ncoonkancoom or, after addition of a strongerformic acid, again for the production of sodium biformate.

of trisodiumhydro ing in adding sodium formate to aqueous formic acid, the percentage of acid of which 18 at least 20%, and-heating.

3. A process for the production of sodium ams of formic acid of about i 4. A process for-the production of sodium formate-forinic acid compounds, consisting in adding sodium formate to aqueous formic acid, the percentage of acid of which is at least 50%, and heating.

5.- A process for the production of a sodium formate formic acid compound, consisting in adding sodium formate to aqueous formic acid, the percentage of acid of which is 20 to 50%, and in converting the trisodiumhydrd formate thus produced into biforniate of sodium by treating it with aqueous formic acid of more than 50% acid content.

6. A process for the production of a sodium' fo'rmate-formic acid compound, consisting in adding sodium for-mate to aqueous formic acid, the percentage'of acid of which is more than continuing the addition until the concentration of the formic acid comes backto 50%, and in converting the trisodiumhydroformate thus produced into biformate of sodium by treating it with aqueous formic acid.

7. A process for the production of a sodi' um formate-formic acid compound, consisting in adding sodium formate to aqueous formic acid, the percentage of acid of which is more than 20%, in separating from the mother liquor the sodium formate-formic.

acid compound thus produced, and in adding to the mother liquor further quantities of sodium formate.

8. A process for the production of a sodium formate-formic acid compound, consistture.

EGON ELoD. 

